/Engine/Source/Runtime/SlateCore/Public/Layout/Geometry.h
Create a child geometry relative to this one with a given local space size, layout transform, and identity render transform. For example, a widget with a 5x5 margin will create a geometry for it's child contents having a LayoutTransform of Translate(5,5) and a LocalSize 10 units smaller than it's own.
The new child geometry.
[FGeometry](API\Runtime\SlateCore\Layout\FGeometry) MakeChild ( const [UE::Slate::FDeprecateVector2DParameter](API\Runtime\SlateCore\Types\FDeprecateVector2DParameter) & InLocalSize, const [FSlateLayoutTransform](API\Runtime\SlateCore\Rendering\FSlateLayoutTransform) & LayoutTransform ) const